Catalytic conversion of acetylene to polycyclic aromatic hydrocarbons over particles of pyroxene and alumina

摘要: Polycyclic aromatic hydrocarbons (PAHs) are known to be present in many astrophysical objects and environments, but our understanding of their formation mechanism(s) is far from satisfactory. In this paper, we describe an investigation the catalytic conversion reaction acetylene gas PAHs over pyroxene alumina. Crystalline silicates such as pyroxenes (with general formula [Mg, Fe]SiO₃) alumina (Al₂O₃) observed astrophysically through infrared spectra likely promote grain surface chemical reactions. experiments reported here, gas-phase were produced by crystalline using a pulsed jet expansion technique gaseous products detected time-of-flight mass spectrometry. separate experiment, was further confirmed with at atmospheric pressure flowing continuously fixed-bed reactor. The effluent carbonaceous compounds deposited on catalysts dissolved separately dichloromethane analysed chromatography-mass Among samples studied, showed higher activity than pyroxene-type grains for reaction. It proposed that relies Mg²⁺ ions Al³⁺ alumina, where these act Lewis acid sites. X-ray diffraction, Fourier transform high-resolution transmission electron microscopy techniques used characterize structure physical properties samples.